Pharmaceutical Compounding I: Liquid Dosage Forms and Solutions, Cheat Sheet of Chemistry

Download Pharmaceutical Compounding I: Liquid Dosage Forms and Solutions and more Cheat Sheet Chemistry in PDF only on Docsity! Pharmaceutical Compounding I Lec 2 : Liquid Dosage forms, Solutions Presented By:Dr Amit Sharma Assistant Professor of the Pharmacy Department 1 Komar university OF SCIENCE AND TECHNOLOGY Outline • Liquid Dosage forms • Pharmaceutical Solution • Solubility • Preparation • Drugs • Solvents • Water • Non Polar • Excipients • Enhancing solubility • Types of pharmaceutical solutions 2 Liquid Dosage forms • One of the major types of dosage form • It comes after solid dosage forms (tablet) 3 Liquid Dosage forms • In pharmacy different kinds of l iquid dosage forms are used • They consist of a dispersion of one or more substances (Drug +Excipients) in a l iquid phase 4 Liquid Dosage forms • Depending on the nature of interaction between solute and solvent 1. True Solution ( molecular) • Sugar dissolved in water 2. Colloidal solution 3. Disperse systems (suspension) • Sand is mixed w i th water • Antibiotics in paediaterics 5 S O L U T I O N • “one phase system of two or more substances” • Two or more substances mixed they wil l be in one state of mat ter and form homogenous mixture • E.g. Solid dissolved in l iquid • States 1. Solid: • Solid in solid, solid in liquid, solid in gas 2. Liquid; • Liquid in l iquid , l iquid in gas 3. Gas : • Gas in gas, gas in l iquid 6 Pharmaceutical Solution • Solutions are preparations in which the solid solutes (drug and excipients) are dissolved in a l iquid solvent system. • Water is the most common solvent • Organic solvents are used in combinat ion w i th water or alone 7 Pharmaceutical Solution • All the components of a solution are dispersed as molecules or ions • the solution is optically clear. • Solutions can be prepared by simple mix ing of the solutes w i th the solvent system. 8 Preparation of solution Drug Solvent Excip ien t s Solution 17 Drug • The drug could be a small molecule like aspirin • Large molecule, such as insulin or an ant ibody 18 Aspirin Insulin Solubility of drugs • Pharmacopoeia Aulton 2017 p28 19 Drug • Drug is present as molecules or ions throughout the solvent. • The drug concentration in a pharmaceutical solution must be below the saturation solubility • Avoid the possibility of drug precipitat ing out of the solvent 20 S o l v e n t s 1. Aqueous 2. Non- Aqueous 21 Aqueous • The majori ty of pharmaceutical solutions are water- based. • Water is the most commonly used solvent due to its many advantages; • Lack of toxicity (biocompatible) • Low cost • Dissolving many medicines • Giving clear solution 22 Ty p e s of w a t e r 1. Tap water • Not used 2. Purified water USP 3. Distil lation 4. Reverse osmosis 5. Ion Exchange 3. Water for Injection (WFI) USP • Sterile and non-pyrogenic 23 Non-aqueous solvents • When used ? 1. The drug is poorly soluble water 2. Not stable in water (hydrolysis ) 3. Non-oral uses • Non- aqueous solutions are however l imi ted to certain delivery routes, such as topical, why ? 1. Unpalatability 2. Toxicity 3. Irritancy 4. Immiscibi l i ty w i th physiological fluids 24 Non-aqueous solvents 1.Alcohol (Ethanol) • The most common organic solvent used in pharmaceutical solutions. • I t is of ten used as a co-solvent in oral, topical and parenteral solutions. 25 Non-aqueous solvents 2. Polyhydric alcohols • Alcohols containing more than one hydroxyl group per molecule a) Propylene glycol: • (CH3CH(OH)CH2OH) contains 2 hydroxyl groups per molecule. • It is often used as a co-solvent in oral, topical, parenteral and otic solutions. b) Glycerol: contains 3 hydroxyl groups per molecule. • It is widely used as a solvent or co-solvent w i th water, in oral and parenteral solutions. 26 Non-aqueous solvents 3.Dimethyl sulfoxide (DMSO) • Used as a carrier for idoxuridine for topical application to the skin. 27 Excipients • Substances other than the drug which are included in pharmaceutical: 1. Enhance product stability, bioavailability or pat ient acceptability 2. Aid product preparation ( Co-Solvents) 3. Identif ication (colour) 28 Oxidation • To reduce photooxidation, solutions are packaged in containers that do not allow l ight transmission. • To reduce oxidation • Antioxidants • Metal chelators (as heavy metal ions catalyse oxidation) are used. 37 Microbiological • To inhibi t microbial g rowth dur ing use • Preservatives are used in mult idose products 38 Enhancement of drug solubility 1. pH adjustment 2. Co-solvents 3. Complexation w i th cyclodextrins 4. Surfactants and micelles 39 C o -s o lve n ts • The principle ‘like dis- solves like’. • Polar drugs generally dissolve in polar solvents • Non-polar drugs generally dissolve in non-polar solvents • Non-polar drugs are poorly soluble in water – a polar solvent. • Polarity of water can be reduced by addit ion of other solvent which is less polar or non-polar 40 C o -s o lve n ts • Examples include • Glycerol • Propylene glycol • Ethanol • The solubility of non-polar drugs in water can be increased by several orders of magni tude using co-solvents. 41 • Surface active agents • One region is hydrophil ic and the other hydrophobic. • Surfactant molecules tend to accumulate at the boundary between two phases, such as water-oil interfaces. 42 • They reduce the surface tension of liquids, and self- assemble to form micelles once the critical micellar concentrat ion (CMC) is reached. 43 Types 44 Use • Oral Solution • Ear drops • Eyedrops • Nasal drops • Mouthwash • Parenteral pulmonary 45